Electric utility companies need to provide and maintain generating facilities and distribution networks which are ample by a safe margin to meet the demand for electric power during periods of peak or maximum demand. Such requirements are needed to maintain their competitive position as suppliers of energy as well as meeting certain governmental regulations. The level of electrical power consumed during other than these peak periods is considerably less than the peak demand; however, to meet the peak demand a considerable investment in generating facilities and distribution networks is needed and yet during a good portion of the time such generating facilities may be idle. To eliminate the investment of several hundred thousand dollars for extra capacity to meet these peak demands, various systems have been used in the past to reduce the demand for electrical energy during the peak periods.
For example, in the control of electric water heaters, timing mechanisms, and even elaborate signaling systems for controlling electric water heaters over the power line by superimposed control signals, have been devised for disconnecting electrical loads during a peak period to reduce the peak demand. Another type of system, such as that shown in the Robert L. Coe U.S. Pat. No. 3,261,992, patented July 19, 1966, is used for selectively disconnecting an electrical refrigeration apparatus when the outdoor temperature exceeds some predetermined value to decrease the peak electrical demand.
The present invention is a device for use with an electrical load apparatus wherein the electrical load increases as some condition such as outdoor temperature increases. As the condition or outdoor temperature increases to result in a greater percent of operation of a refrigeration apparatus, the device is reset or modified so that as the outdoor temperature increases the actual percent "on time" of the refrigeration apparatus is reduced from a normal or desired mode of operation. Specifically, a temperature responsive switch device responds to ambient or outdoor temperature. The switch device is placed in the control circuit of the refrigeration apparatus to stop the operation of the refrigeration apparatus when the temperature of a sensing device exceeds some predetermined temperature value. The control temperature of the temperature responsive switch device is changed by heat from the refrigeration condenser depending upon the amount of operation of the refrigeration apparatus. The refrigeration apparatus is operated in a shorter "on" cycle manner as the outdoor temperature increases thus reducing use of electrical energy.